1. Field of the Invention
This invention relates to an image forming apparatus having an electric sorting function, and more particularly to an image forming apparatus which has a function of detecting and eliminating avoidable image reading operations after a sample set is output during a time of reproducing multiple print sets.
This invention also relates to a method of performing the above-mentioned function.
2. Discussion of the Background
In recent years, there have been great advances for an image forming apparatus such as a digital copying machine to become a multifunction product aiming to improve ease of use, productivity, and so forth. As an example of this trend, many such image forming apparatuses include a utility apparatus, such as, an automatic document feeding apparatus (hereinafter referred to as an ADF), an automatic sorting apparatus (hereinafter referred to as a sorter), and so forth.
In an ADF-installed image forming apparatus, for example, an improvement has been made in such a way that an original document which includes a number of sheets placed on a document bed of the ADF is automatically transferred to a reading position on a contact glass sheet by sheet. Subsequent operations, such as, a reading operation, an ejection operation in which the read sheet of the original document is ejected to a predetermined eject tray, and so forth, are also executed in a continuously automated manner. Thus, a user is freed from the repetitive actions of placing and removing a sheet of the original document onto the image forming apparatus over and over again.
A sorter is another utility apparatus which provides an image forming apparatus with a feature for reducing an operation time during a multiple copying operation of an original document including multiple sheets. One exemplary use of such a sorter is disclosed in the official gazette of the Japanese Laid Open Patent Application TOKUKAI HEI 1-236169. In this exemplary use of a sorter in combination with a copying machine or the like, any copied sheet corresponding to a sheet after a first sheet of the original document is automatically sorted on the basis of a required number of a multiple copy stored in a memory.
Further, a copying machine disclosed in the official gazette of the Japanese Laid Open Patent Application TOKUKAI HEI 1-316066 teaches an effective way of using a memory for storing images of an original document including multiple sheets so as to be able to electrically sort the images while these images are held in the memory and before starting an image forming operation on a photoconductive drum or the like. As a result, this function for electrically sorting images can eliminate multiple eject trays for selectively receiving multiple copy sheets and consequently the copying machine can be made relatively smaller.
Further, an image forming apparatus which includes a sorter disclosed in the official gazette of the Japanese Laid Open Patent Application TOKUKAI HEI 2-90183 teaches a unique method of using the sorter.
Further, in the official gazettes of the Japanese Laid Open Patent Applications TOKUKAI HEI 5-107852 and TOKUKAI HEI 6-95463, image forming apparatuses are described which are capable of providing a sample set for an operator's visual checking during a time of reproducing multiple copy sets. These inventions enable the operator to change various image forming modes so as to output remaining copy sets in a desired image mode.
However, in the above-mentioned background image forming apparatus having a copy sample serving function, there has been a problem in that, after viewing the sample, the operator is required to place the original document back into a predetermined position in order to proceed with a further operation for outputting the remaining copy sets. For example, in a case when an image forming mode is changed due to a result of the check on the copy sample, the operator is required to place the original document into the predetermined position once again in order to restart a copying operation. In addition, when such an image forming apparatus includes an ADF, the original document must be subjected to an automatic transferring operation once again in which the original document is moved by rubbing friction force by the ADF. Therefore, in this case, the original document may possibly be damaged in a relatively short time.